Department of Geology and Graduate Program in Evolution, Ecology and Behavior, University at Buffalo, Buffalo, New York, United States of America.
PLoS One. 2013 Sep 6;8(9):e74587. doi: 10.1371/journal.pone.0074587. eCollection 2013.
Disturbance events are an important component of the ecology of coral reefs and increasingly frequent disturbances coupled with a lack of population resilience may contribute to changes in the structure of coral reef communities. The harvest of the Caribbean octocoral Antillogorgia elisabethae provides an opportunity to explore the relationship between adult abundance and recruitment and the manner in which recruitment contributes to the resilience of local populations. Recruitment of A. elisabethae was monitored in 20, 1-m(2) quadrats at 8 sites along the southern edge of the Little Bahama Bank from 2004 through 2007. A. elisabethae has been harvested in The Bahamas for over fifteen years and all of the sites had been harvested three times, including a harvest during the course of the study. Abundances of adult colonies at those sites as well as a location that had not been harvested were also determined. Recruitment was highly variable, differing between sites, transects within sites, and, depending on the site, between years. Recruitment was best correlated with adult abundance averaged across the surrounding site. Regression analyses suggest abundance on smaller scales had only small effects on recruitment. The effects of the harvesting were site specific ranging from a 38 to 67% reduction in the density of mature colonies. The sites with the most abundant A. elisabethae continued to have the highest abundances after harvesting and there was no significant difference in recruitment before and after harvesting. Population size-structure at 6 of 8 sites that have been harvested multiple times exhibited an overall depletion in small colonies suggesting long term suppression of recruitment and declining populations. Severe depression of adult abundances coupled with local recruitment can create a negative feedback and lead to the decline of local populations. Populations that are dependent on self-recruitment are not resilient to large disturbance events.
干扰事件是珊瑚礁生态学的一个重要组成部分，越来越频繁的干扰加上种群恢复力不足，可能导致珊瑚礁群落结构发生变化。加勒比海八放珊瑚 Antillogorgia elisabethae 的收获为探索成年丰度与补充之间的关系以及补充对当地种群恢复力的影响提供了机会。2004 年至 2007 年期间，在小巴哈马滩南部边缘的 8 个地点，用 20 个 1 平方米的样方监测了 A. elisabethae 的补充情况。在巴哈马群岛，A. elisabethae 的收获已经超过十五年了，所有的地点都已经收获了三次，包括在研究过程中的一次收获。还确定了这些地点以及一个未收获地点的成年群体丰度。补充情况变化很大，不同地点、地点内的样线以及取决于地点的年份之间都有差异。补充情况与周围地点的成年丰度平均值相关性最好。回归分析表明，较小尺度上的丰度对补充的影响很小。收获的影响是特定于地点的，从成熟群体密度减少 38%到 67%不等。A. elisabethae 最丰富的地点在收获后继续保持最高的丰度，收获前后补充没有显著差异。在多次收获的 8 个地点中的 6 个，种群大小结构表现出小群体的总体减少，这表明长期抑制了补充和下降的种群。严重的成年丰度下降加上当地的补充，可以形成一个负反馈，导致当地种群的下降。依赖自我补充的种群对大的干扰事件没有恢复力。
